"It is regrettable that it will be hard to open the plenary session today," National Speaker Moon Hee-sang said on the floor.

"The National Assembly does not fulfill its responsibility if it does not handle urgent bills linked to people's lives and it neglects its duty," he added.

The LKP and BP control a combined 142 seats in the 299-member parliament.

The passage of bills requires the attendance of a majority of the current lawmakers and majority approval. The quorum for the votes was not met on Thursday.

Their boycotting of parliamentary schedules will likely delay the National Assembly's review of the government's 2019 budget proposal and passage of key bills on the economy.

The two parties called on Moon on Tuesday to sack his senior aide for civil affairs for failing to properly vet the minister before his nomination.

They also urged the ruling Democratic Party (DP) to accept a parliamentary probe into an allegation that the Seoul subway operator gave unfair job favors to its employees. The parties vowed not to cooperate with the DP if their two requests are rejected.

Earlier in the day, the floor leaders of the rival parties held a closed-door meeting to break the current stalemate, but they failed to reach a compromise.

The DP denounced the two parties for scuttling the session at a time when parliament should do its part to help prop up the slowing economy.

"It is not understandable that they boycotted the meeting while making an unreasonable demand," Hong Young-pyo, the DP's floor leader, said. 

Kim Kwan-young, the BP's floor leader, claimed that negotiations broke down as the ruling party kept mum toward their demand for a probe into the hiring scandal.

Meanwhile, the sub-panel of the public administration committee is expected to deliberate on a bill aimed at toughening punishment for drunk driving Tuesday.

Rival parties earlier agreed to swiftly handle the legislation that calls for heavier penalties for drunk drivers and stricter standards of blood alcohol level. It has been pending at parliament since October.

The bill is called the Yoon Chang-ho act, after a 22-year-old soldier who died last week after being in a coma since he was struck by a drunk driver in the southern port city of Busan in September. (Yonhap)